Gas burner



Oct. 5, 1948. A. H. GREAVES GAS BURNER Filed May 27, 1943 1.?f/Zf6JZfZOfS #44, J 6 296 a Mes Patented Och 5,

; v 90 OFFICE GAS BURNER Albert Horace Greaves, London,

England, assignor of forty per cent to Ronald Victor Short, Haxby,

England Application May 27, 1943, Serial No. 488,720 In Great Britain June 16, 1942 4 Claims. (Cl. 158-118) 1 This invention relates togas burners of the injector type in which the burner jet is arranged centrally within the bell mouthed or enlarged lower end of the mixing tube, the orifice being located in the throat of the mixing tube immediately above the upper edges of the air inlet holes, the jet immediately surrounding the orifice being of part conical shape and in conjunction with the throat providing an intervening annular passage through which air entering the inlet holes must pass to enter the upper part of the mixing tube.

In order that the said invention may be clearly understood and readily carried into effect, the same will now be described more fully with reference to the accompanying drawings, wherein:

Figure 1 is a longitudinal vertical section of a gas burner constructed in accordance with the invention;

Figure 2 is a transverse section on the line IIII in Figure 1;

Figure 3 is a transverse section on the line IIIIII in Figure 1; and

Figure 4 is an enlarged fragmentary longitudinal sectional detail of the lower part of Figure 1.

In the preferred, embodiment of the invention illustrated, the jet I having a central orifice la is-located in position within the lower end of a mixing tube 2 which is provided with radially arranged air admission holes 3 around its periphery, the discharge end of the jet orifice la being located at a point slightly above the upper edges of the air admission holes, the portion of the jet immediately surrounding the orifice being of part conical shape.

The interior of the mixing tube 2 immediately above the air admission holes 3 tapers sharply inwardly as at 4 to form the throat and terminates in a parallel sided boring 5, the mixing tube at its upper end 5 being externally of partconical shape. It is preferred that the width :1: of the annular space 1 separating the part conical surface of the jet from the part conical inner surface or inwardly tapered part 4 of the mixing tube shall be not less than one-sixth and not more than one-third the diameter y of the parallel sided boring 5 in the upper part of the mixing tube.

A second mixing tube 8 is maintained in spaced relationship with the first mixing tube 2 by .engagement of the lower threaded end of the tube 8 with the internal threads of a flange-like sleeve 9 on the upper end of the tube 2. The sleeve 9 is provided with air admission holes l0 aroundits periphery, the air entering the second mixing tube through the annular space H surrounding the part conical extremity 6 of the first mixing tube and the lower edge I: of the second mixing tube.

The second mixing tube is shaped interiorly as at ll in the form of a venturi, the constriction 8a being situated at a point near the ex tremity of the first mixing tube, said extremity being situated at a point between the constriction 8a and the upper edges of the holes Ill, the internal bore of the second mixing tube progresslvely s ng from the constriction to its extremity it which constitutes the burner mouth or alternatively leads to a separate gas burner or burners either directly or by way 01 a pipe.

It is preferred that the distance p separating the upper edges of the air inlet holes in from the upper extremity of the first mixing tube 2 shall be not less than the internal diameter q of the constriction Be.

With the arrangement hereinbefore described.

initial mixing of the gas and air takes place in the first mixing tube 2, while further air is admitted through the inlet holes Ill provided in the tubular sleeve or gallery 9, the additional air passing into the second mixing tube 8 through the annular space I I formed between the part conical end of the first mixing tube and the interiorly coned lower end of the second mixing tube while, due to the Venturl shape'of the second mixing tube, a steady flow of air into both mixing tubes is entrained, the additional air mixing with the admixture of air and gas either in or issuing from the first mixing tube. In this way, the mixture has a very high air content, a large quantity of air being sucked in as a result of the injector action of the air and gas mixture issuingfrom the first mixing tube. Furthermore, it is found that it is virtually impossible to cause the burner to light bac at the air admission holes or jet orifice and while having very highheating propertles, the flame produced is fected by draughts.

It has been found that when the gas control cock is turnedlow to a pilot light, the flame is luminous, but as the cock is opened the flame is progressively aerated.

Iclaim:

' 1. A gas burner comprising in combination an air-gas mixing tube having a conical outer end and having a bore provided with an inwardly tapering throat and provided with air inlet openings through the wall of the bore which open to the interior of the tube immediately beneath stable and unafthe threat, the throat dividing the bore of the tube into two parts of different diameters, a gas jet fitted into the part of the air-gas mixing tube bore of larger diameter so the tube and terminating at its outlet adjacent the throat of the air-gas mixing tube and inter mediate the larger and smaller bore-parts, the

outer surface of'th'e-gas' jet at its 'said'extremity being also of tapering frusto-conical shape so that an axially inclined annular space is provided I as to; be co-axial with 3 between the jet and the throat, the width of said annular space being not less than one-sixth'and not more than one-third of the diameter'oi the portion of the bore immediately thereabove an internally threaded sleeve carried by the first tube and arranged in concentric spaced relation with the outer conical end thereof and provided with air admission holes at its inner end, a second mixing tube having its inner end in threaded engagement with the threaded portion 01' the sleeve and having a bore and a venturi throat inthe bore, the throat of the venturi being arranged slightly beyond the outer end or the first tube while the inner part oi the venturi surrounds the conical end of the first tube in spaced relation to provide a second inclined annular space which produces an ejector effect by which additional air may be drawn through the airadmission holes into the air-gas mixture which issues from the said outlet end of the first mixing tube, and the distance between the upper edges of the holes in the sleeve and the outer extremity of the first mixing tube being not less than the internal diameter of the throat of the venturi.

2. A gas burner comprising in combination an air-gas mixing tube having a frusto-conical outer end and having an intermediate portion of the bore thereof providedwith an inwardly tapering throat and provided with air inlet openings through its sides which open to the interior of the tube immediately beneath the throat, the

- throat dividing the bore of the tube into two parts of different diameters, a gas jet means fitted into the bore of the air-gas mixing tube of larger diameter so as to be coaxial with the tube and tarminating at its outlet and centrally within the throat of the air-gas mixing tube and intermediate the larger and smallerends of the said.

tube portion, the outer surface of the gas jet at its said extremity being also of tapering frustoconical shape so that an axiallyinclined annular space is provided between the jet and the throat, the width of such annular space being not less than one-sixth nor more than one-third of the smaller diametered part of the said mixing tube, an internally threaded sleeve carried by the first tube and arranged in concentric spaced relation with the frusto-conical outer end thereof and provided with air admission holes at its inner end, a second mixing tube having its inner end in threaded engagement with the threaded portion of the sleeve and having a venturi shaped inner surface which is located relatively to the irusto-conical outer end of the first tube to provide a second inclined annular space which produces an ejector effect by which additional air may be drawn into the air-gas mixture which issues from the said outlet end of the first mixing tube.

3. A gas burner comprising in combination an air-gas mixing tube having a bore having portions 0! larger and smaller diameter and an inwardly tapering throat which merges at its ends into portions of the bore of larger and smaller diameter, a gas jet means fitting in the bore of larger diameter so as to be coaxial with the tube andhaving its extremity through which the gas issues disposed to terminate intermediate the ends of the said throat such that an axially inclined annular space is provided between the outer surface of the jet and the adjacent tapering throat of the bore, the width of such annular space being not less than one-sixth nor more than one-third of the smaller diametered part or the annular space, a second mixing tube having a bore in the form 01? a. venturi arranged as a coaxial extension of the first such tube and having its bore of larger diameter than that of the portion or the other tubev which is of the smaller diameter, and means for connecting the said tube to the first tube comprising a sleeve carried by and surrounding the outlet end of the first mixing tube andlliaving openings therein through which additional air is admitted into the second mixin tube, said sleeve being in emally screw-threaded to receive an externally screw-threaded portion on the inner end of the second mixing tube.

4. A gas burner comprising in combination an air-gas mixing tube having a bore having portions 01 larger and smaller diameter and an inwardly tapering throat which merges at its ends into portions of the bore of larger and smaller diameter, a gas jet means fitted in the bore of larger diameter so as to be coaxial with the tube and having its extremity through which the gas issues disposed to terminate intermediate the ends of the said throat such that an axially inclined annular space is provided between the outer surface of the jet and the adjacent tapering throat of the bore, the width of such annular space being not less than one-sixth nor more than one-thi d of the smaller diametered part of the said in xing tube; the wall 0! the portion of the mixing tube of larger diameter having openings therein immediately beneath the tapering throat through which air can be admitted into said annular space, a second mixing tube having a bore in the form of a venturi arranged as a coaxial extension of the first such tube and having its bore of larger diameter than that of the portion of the other tube which is of the smaller diameter, and means for connecting the said second tube to the first tube, comprising a cylindrical sleeve integral with the first tube and arranged in spaced concentric relation with the outer end thereof and having openings therein through which the additional air is admitted into the second-mixing tube, said sleeve being internally screw-threaded to receive an externally screw-threaded portion at the inner end of the second mixing tube.

ALBERT HORACE GREAVES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED srA'rEs PATENTS 

